A large number of pipeline trenching and laying devices have been developed, in part a response to the demand for more buried utility lines. However, the economical burying of pipe requires increasingly sophisticated equipment to reduce the labor that would otherwise have to be expended in the effort. Additionally, as the price or real estate rises, the cost of pipeline easements also rises. It therefore becomes increasingly important to be able to utilize narrower easements.
One problem that has been inadequately addressed by previous pipeline trenching and laying devices is the need to support the sidewalls of a trench until the pipe is laid at the bottom of the trench. As a result, most trenches are overly wide; this allows some sidewall collapse to take place without preventing pipe burial at the desired depth. However, by making the trench overly wide, a considerably greater amount of energy is expended. This adds to the time, expense and equipment requirements of the operation.
A further problem that has been inadequately addressed by previous pipeline trenching and laying devices is the need to provide a pipe feed chute that provides the means to control the exact curvature of the pipe as it is laid into the trench. Some curvature is required; however, too great a curvature can result in a kink or a rupture of the pipe. The degree of curvature that a pipe can withstand is a function of many variables, including the diameter of the pipe and the materials used in the construction of the pipe. The amount of curvature required to bury the pipe depends on many variables, including the depth to which the pipe is to be buried. Known pipeline trenching and laying devices have not provided the means to properly control these variable, and therefore control the curvature of a pipe as it is laid in a trench.
A still further problem that has been inadequately addressed by previous pipeline trenching and laying devices is the need to provide a pipe feed chute that is capable of conforming to the sides and bottom of the trench even as the trench is first started, and the plow has not yet achieved its travel depth. The difficulty is related to the changing elevation of the plow as it reaches it cutting depth. Where the pipe feed chute fails to conform to the parameters of the trench cut by the plow, additional friction will result. Previous pipeline trenchers have not disclosed well-developed feed chutes, and structures addressing this issue have generally been missing.
What is needed is a pipeline trenching and laying apparatus that can control the curvature of the pipe, taking into account the pipe's diameter, materials of construction and the depth of the trench. The apparatus must also provide structures that minimize the width of the required trench, and that prevent sidewall collapse. The apparatus must provide a well-developed feed chute that adapts to changes in the elevation of the trench floor. Such an apparatus would be a considerable advance in the field of pipeline trenching and laying devices.